2022-08-28 update: added "Sort the Matrix Diagonally" (#76)

Author: fartem

Diff for: src/main/java/com/smlnskgmail/jaman/leetcodejava/medium/SortTheMatrixDiagonally.java

@@ -0,0 +1,52 @@
+package com.smlnskgmail.jaman.leetcodejava.medium;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class SortTheMatrixDiagonally {
+
+    private final int[][] input;
+
+    public SortTheMatrixDiagonally(int[][] input) {
+        this.input = input;
+    }
+
+    public int[][] solution() {
+        int rows = input.length;
+        int cols = input[0].length;
+        List<Integer> diagonals;
+        for (int r = 0; r < rows; r++) {
+            int i = r;
+            int j = 0;
+            diagonals = new ArrayList<>();
+            while (i < rows && j < cols) {
+                diagonals.add(input[i++][j++]);
+            }
+            Collections.sort(diagonals);
+            i = r;
+            j = 0;
+            int k = 0;
+            while (i < rows && j < cols) {
+                input[i++][j++] = diagonals.get(k++);
+            }
+        }
+        for (int c = 0; c < cols; c++) {
+            int i = 0;
+            int j = c;
+            diagonals = new ArrayList<>();
+            while (i < rows && j < cols) {
+                diagonals.add(input[i++][j++]);
+            }
+            Collections.sort(diagonals);
+            i = 0;
+            j = c;
+            int k = 0;
+            while (i < rows && j < cols) {
+                input[i++][j++] = diagonals.get(k++);
+            }
+        }
+        return input;
+    }
+
+}

Diff for: src/test/java/com/smlnskgmail/jaman/leetcodejava/medium/SortTheMatrixDiagonallyTest.java

@@ -0,0 +1,19 @@
+package com.smlnskgmail.jaman.leetcodejava.medium;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertArrayEquals;
+
+public class SortTheMatrixDiagonallyTest {
+
+    @Test
+    public void defaultTest() {
+        assertArrayEquals(
+                new int[][]{{1, 1, 1, 1}, {1, 2, 2, 2}, {1, 2, 3, 3}},
+                new SortTheMatrixDiagonally(
+                        new int[][]{{3, 3, 1, 1}, {2, 2, 1, 2}, {1, 1, 1, 2}}
+                ).solution()
+        );
+    }
+
+}